1. Field of the Invention
The present invention relates to connectors for joining the ends of successive lengths of pipe or conduit and/or connecting a pipe or conduit to a bracket, flange, housing or other mounting surface wherein the connection will be exposed to axial transverse and bending vibrations. In particular, the present invention relates to connectors for joining pipes to one another or to other structures in exhaust systems for vehicles.
2. The Prior Art
It is well known that, in vehicle exhaust systems, particularly those for heavy duty vehicles, such as large trucks or earth moving equipment, the internal combustion (i.c.) engines produces significant amount of vibration in the exhaust system. Operation of the motors at continuous speeds for prolonged periods of time can, especially, produce what are known as harmonic vibrations which can cause significant deflections in extended lengths of exhaust pipe and at locations where such pipes are mounted to structures such as brackets, engine manifolds, and the like. Repeated deflections and vibration along the exhaust pipe system can, in turn, cause the structures to weaken with time and ultimately fail. Further, such harmonic vibrations can also be transmitted through the exhaust pipes to the mountings of the pipes, promoting the loosening of the mountings, which can result in the sudden displacement of one or more components of the exhaust system, with the potential for both personal injury and equipment damage.
In addition to the vibrations caused by the operation of the motor of the vehicle, an exhaust system is also subjected to various tension, compression and bending forces, which also arise during the operation of the vehicle. While individual exhaust system components could be made stronger and more massive to resist failure by fatigue, such constructions would be undesirable due to weight considerations. Further, by making individual elements stiffer, the vibrations are merely transmitted throughout the exhaust system to the mountings or other components and are not reduced or eliminated. Accordingly, it is desirable to isolate the exhaust system, or at least components of the system, from such vibrations and forces.
It is known that if the pipes of an exhaust system are divided and separated by non-rigid connections, rather than being constructed as continuous extended lengths, the development of harmonic vibrations from the motor is precluded or reduced. Such non-rigid connections can be advantageously employed to absorb other tension, compression and bending forces, apart from and in addition to the motor vibration.
It is therefore desirable to provide a connector for joining a length of exhaust pipe, to another pipe or to a mounting, such as an engine manifold, which connector joins the components in a non-rigid fashion and is capable of absorbing tension, compression, and bending forces, as well as the vibrational forces, without transmitting them from one exhaust system component to another.
Typical prior art flexible connectors often require welds at both ends, in order to achieve a strong, substantially fluid-tight connection between the connector and the other exhaust system components to which they are attached. It would be desirable to avoid the use of welds whenever possible, as such welds take time to perform, adding to the installation time of the connector, and increasing the overall assembly time of the vehicle or apparatus to which they are being attached.
In addition, such welds are often difficult to place properly, often requiring additional complexity in the construction of the flexible connector, in order to provide working space for accomplishment of the weld. Still further, there is always the possibility of a small flaw in the weld, leading to possible leakage of harmful exhaust gases, and/or the introduction of a physical weakness in the structure of the flexible connector attachment, leading to the expenditure of additional time for double-checking the quality of each weld being performed.
In some instances, a weld is undesirable, and in order to provide for some form of sealing, gaskets must be positioned at the interface between the flexible connector and the exhaust manifold or other component to which the connector is being attached. Such gaskets which are usually made from mica coated stainless steel, for example, could begin to experience leakage shortly after installation, and, presuming an exhaust manifold pressure in the vicinity of 4.5 psig, could have a leakage rate of over 0.5 liters per minute.
It would be desirable to provide an alternative to welding for the manufacture and/or installation of flexible connector apparatus, which would be less expensive, require less intensive examination upon completion and/or have an enhanced degree of reliability and/or manufacturability than welding techniques.
It would be desirable to provide a flexible connector apparatus and a method and apparatus for the manufacture and installation of it, which would employ fewer welds.
It would also be desirable to provide a weldless connection between a flexible connector apparatus and a component, such as an exhaust manifold, which does not rely upon the use of gaskets, which may deteriorate with use, and which could experience leakage when in use.
These and other desirable characteristics of the invention will become apparent in view of the present specification including claims, and drawings.
The present invention comprises, in part, a flexible connector apparatus for connecting first and second components of a fluid conduit system, such as an exhaust system for an internal combustion engine. The apparatus comprises a bellows member, having an axis, first and second ends, and at least two substantially uniform convolutions disposed substantially adjacent the first of the two ends; and a flange member, positioned in circumferentially surrounding relationship to the bellows member, axially between the at least two substantially uniform convolutions of the bellows member.
The flange member includes at least one attachment element, operably associated with the flange member and configured for attachment of the flange member to one of the first and second components of the fluid conduit system.
The attachment element further is configured to capture one of the at least two substantially uniform convolutions axially between the flange member and the one of the first and second components of the fluid conduit system, for forming, upon completed attachment of the flange member to the one of the first and second components, a substantially fluid-tight weldless seal between one of the at least two substantially uniform convolutions of the bellows and the adjacent end of the bellows member, and the one of the first and second components.
The axially opposite end of the bellows member is operably configured for attachment at least indirectly to the other of the first and second components, for forming a substantially fluid-tight connection therewith, toward enabling the substantially fluid-tight transportation of fluid from the one of the first and second components, through the flexible connector apparatus, to the other of the first and second components.
The flexible connector apparatus further comprises, in one embodiment, a liner tube structure insertably received within the bellows member. The liner tube structure, in turn, may comprise a first liner tube member having a radially outwardly extending annular flange at one end thereof, the first liner tube member being insertably received in the first end of the bellows member, such that at least a portion of one of the at least two substantially uniform convolutions is positioned axially between the flange member and the radially outwardly extending annular flange member, such that upon capture of the convolution between the flange member and the one of the first and second components, the radially outwardly extending annular flange member is also captured thereby; and a second liner tube member, telescopically engaged with the first liner tube member and insertably received within the bellows member, at a position distal to the first end of the bellows member, being operably configured for attachment at least indirectly to the other of the first and second components, for forming a substantially fluid-tight connection therewith, toward enabling the substantially fluid-tight transportation of fluid from the one of the first and second components, through the flexible connector apparatus, to the other of the first and second components.
A first substantially resilient spacer member is radially disposed between the telescopically engaged first and second liner tube members. Axially spaced first and second stop members, may be operably associated with the first and second liner tube members, respectively, for axially engaging the first spacer member therebetween, and limiting extensive axial movement of the first and second liner tube members relative to one another.
An end cap member may be provided, circumferentially surrounding a portion of the second end of the bellows member and a portion of the second liner tube member distal to the first liner tube member.
A second end cap member may be provided, circumferentially surrounding a portion of the first end of the bellows member and a portion of the first liner tube member distal to the second liner tube member, a portion of the second end cap member in turn being circumferentially surrounded by the flange member.
In an alternative embodiment of the invention, the bellows member is fabricated from at least two telescopically engaged tubular members, so that at least an innermost one of the tubular members overlaps others of the tubular members and, at least at the end proximate the flange member, extends axially beyond at least one other of the tubular members.
An end cap member may be provided, circumferentially surrounding a portion of the member, a portion of the end cap member in turn being circumferentially surrounded by the flange member.
In another embodiment of the invention, the convolution which is disposed between the flange member and the proximate end of the member is formed from a layer of no more than two telescopically engaged tubular members.
The present invention also comprises a method for manufacturing a flexible connector apparatus, for connecting first and second components of a fluid conduit system, such as an exhaust system for an internal combustion engine, comprising the steps of:
forming a first tubular member, having two ends;
forming a flange member, having an aperture therethrough having an inside diameter which is substantially equal to but greater than an outside diameter of the first tubular member;
configuring at least one attachment element on the flange member to enable attachment of the flange member to one of the first and second components;
inserting the first tubular member into the aperture of the flange member, to a position proximate one of the two ends of the first tubular member;
forming a plurality of at least two annular substantially uniform convolutions in the first tubular member, each such convolution having an outside diameter greater than the outside diameter of the first tubular member,
subsequent to formation of the at least two substantially uniform convolutions, the flange member being positioned between and substantially abutted by two of the at least two substantially uniform convolutions.
In one embodiment of the method, the method further comprises the steps of:
inserting a liner structure into the first tubular member after formation of the at least two substantially uniform convolutions; and
mechanically connecting the liner structure to the first tubular member.
The step of inserting a liner structure further comprises the steps of:
forming a first liner tube member having a diameter, which is, less than the diameter of the first tubular member;
forming an second liner tube member having a diameter which is less than the diameter of the first tubular member and predominantly less than the diameter of the first liner tube member;
telescopically inserting the second liner tube member into the first liner tube member, so that a portion of the first liner tube member overlaps a portion of the second liner tube member.
The step of inserting a liner structure may further comprise the step of:
positioning at least a first substantially resilient spacer member radially between the first liner tube member and the second liner tube member.
The method may further comprise the step of:
preparing the end of the first tubular member, proximate the flange member, so that, upon attachment of the flexible connector apparatus to one of the first and second components, one of the convolutions becomes entrapped and compressed between the flange member and the one of the first and second components, to form a substantially fluid-tight seal therebetween, toward precluding escape of fluid therefrom.
Preferably, the step of inserting the first tubular member into the aperture of the flange member, to a position proximate one of the two ends of the first tubular member further comprises the step of:
inserting an end cap member over the first tubular member, a portion of the end cap member being radially enclosed by the first tubular member and the flange member.
Alternatively, the method may further comprises the steps of:
forming one or more second tubular members, having a diameter less than the diameter of the first tubular member; and
inserting the one or more second tubular members into the first tubular member, so that at least the first tubular member overlaps the one or more tubular members, and at least at the end proximate the flange member, extends axially beyond at least one of the one or more tubular members.
The step of forming a plurality of at least two substantially uniform convolutions may further comprise the step of:
forming the convolution which is to be disposed between the flange member and the proximate end of the member preferably from a layer of no more than two telescopically engaged tubular members, although one or three layers may be used, if desired.
The present invention is also directed to an alternative embodiment of a flexible connector apparatus, for flexibly connecting first and second components of a fluid conduit system, such as an exhaust system for an internal combustion engine.
The flexible connector of this alternative embodiment comprises an attachment flange, having an aperture therethrough having an inside diameter, the attachment flange having first and second sides. At least one attachment element is disposed on the attachment flange to enable attachment of the attachment flange to one of the first and second components of a fluid conduit system, by means for prompting the second side of the attachment toward against a surface of the one of the first and second components of a fluid conduit system.
A liner tube assembly has a first end and a second, opposite end, the first end having an outer diameter that is substantially equal, in dimension, to the inside diameter of the aperture of the attachment flange. The first end of the liner tube assembly is positioned within and substantially sealingly affixed to the inside surface of the aperture of the attachment flange at the first side of the attachment flange.
The liner tube assembly is operably configured to accommodate relative movement between the first and second components of a fluid conduit system, when the apparatus is affixed to the one of first and second components of a fluid conduit system.
A tubular sealing member has at least one circumferential corrugation along its length, and a cylindrical collar.
The cylindrical collar of the tubular sealing member is positioned within the second side of the attachment flange, within the aperture of the attachment flange. The at least one circumferential corrugation is placed adjacent the second side of the attachment flange.
Upon attachment of the attachment flange to the one of the first and second components of a fluid conduit system, the at least one corrugation of the sealing tube member becomes captured and subsequently compressed between the second side of the attachment flange and the surface of the one of the first and second components of a fluid conduit system, to create a substantially gas-tight seal between each of the at least one corrugation, the one of the first and second components of a fluid conduit system, and the attachment flange.
The seal created by the tubular sealing member combines with the seal between the liner tube assembly and the attachment flange combining to enable the flexible connector apparatus to establish a substantially gas-tight fluid transport path between the first and second components of a fluid conduit system.
The first end of the liner tube assembly and the cylindrical collar of the tubular sealing member preferably are configured so that upon positioning of the at least one circumferential corrugation against the second side of the attachment flange, an end of the cylindrical collar is positioned within the first end of the liner tube assembly.
The liner tube assembly preferably comprises a bellows, having at least one circumferential corrugation along its length, and first and second cylindrical necks at opposite ends of the bellows; and overlapping inner and outer liner tubes, each of the inner and outer liner tubes having an inner end and an outer end, wherein the inner end of the outer liner tube overlaps the inner end of the inner liner tube, the inner and outer liner tubes being insertingly received within the bellows, wherein the first cylindrical neck of the bellows is affixed to the outer end of the inner liner tube and the second cylindrical neck of the bellows is affixed to the outer end of the outer liner tube, the inner and outer liner tubes being configured for accommodating axial movement relative to one another.
The liner tube assembly preferably further comprises at least one damping member encircling the inner liner tube member, and at least two stop elements disposed on the inner and outer liner tube members, operably configured for axially abutting the at least one damping member when the inner and outer liner tube members undergo relative axial movement.
The at least one damping member and the at least two stop elements may be disposed so that the at least two stop elements axially abut the at least one damping member when the inner and outer liner tube members undergo relative axial movement resulting in increased overlapping of the inner and outer liner tube members.
The at least one damping member and the at least two stop elements may be disposed so that the at least two stop elements axially abut the at least one damping member when the inner and outer liner tube members undergo relative axial movement resulting in decreased overlapping of the inner and outer liner tube members.
In a preferred embodiment of the invention, the at least one damping member comprises two damping members, and the at least two stop elements comprise at least three stop elements, that are disposed so that stop elements axially abut one of the two damping members when the inner and outer liner tube members undergo relative axial movement resulting in increased overlapping of the inner and outer liner tube members, and stop elements axially abut another of the two damping members when the inner and outer liner tube members undergo relative axial movement resulting in decreased overlapping of the inner and outer liner tube members.
The liner tube apparatus may further comprise at least one end cap member, having a collar portion circumferentially surrounding at least a portion of a collar of one of the ends of the bellows, and further having a bell portion circumferentially surrounding the at least one corrugation of the bellows.